This specification relates to advertising.
Online video is a growing medium. The popularity of online video services reflects this growth. Advertisers see online video as another way to reach their customers. Many advertisers are interested in maximizing the number of actions (e.g., impressions and/or click-throughs) for their advertisements. To achieve this, advertisers make efforts to target advertisements to content, such as videos, that are relevant to their advertisements.
When an advertiser wishes to target advertisements to a video, the advertiser can target the advertisements to the video as a whole. For example, if videos are classified into categories, the advertiser can target advertisements to the videos based on the categories.
Targeting the video as a whole, however, may not be optimal for all situations. The subject matter of a video can change within the duration of the video. An advertisement that is relevant to subject matter that is presented at one point in the video may not be as relevant to subject matter that is presented at another point in the video.